This read-write INTEGER (0-2147483647) defines the maximum number of dynamic MAC addresses that can be associated with a locked interface, not relevant in disabled limitation mode, per the description. Admins set this to cap how many devices can be simultaneously learned on a locked port, useful for allowing a small, bounded number of hosts (such as a phone plus a PC) rather than either a single device or unlimited learning. For example, setting this to 2 on a port feeding an IP phone with a daisy-chained PC allows both devices to be learned while still blocking any additional, unauthorized device.